Wheel localizer, wheel localization device, system, method and computer program for locating a position of a wheel

ABSTRACT

Embodiments can provide a system, a wheel localizer, a wheel localization device, a method or a computer program for locating a position of wheel. The system for locating the position of the wheel on the vehicle includes a detector for obtaining information related to a steering angle of the vehicle and a locator for determining the position of the wheel based on the information related to the steering angle of the vehicle. Embodiments further provide a device, a method and a computer program configured to determine information related to one or more expected rotational frequencies of one or more wheels of a vehicle. The device includes a path detector configured to determine expected path lengths of the one or more wheels of the vehicle based on information related to a path of the vehicle. The device further includes a controller configured to determine the information related to the one or more expected rotational frequencies of the one or more wheels of the vehicle based on the expected path lengths of the one or more wheels.

REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.61/693,509 filed on Aug. 27, 2012.

FIELD

Embodiments of the present disclosure relate to a wheel localizer, awheel localization device, a method, a system and a computer program forlocating a position of a wheel, and a device, a method and a computerprogram configured to determine information related to one or moreexpected rotational frequencies of one or more wheels of a vehicle.

BACKGROUND

Tire Pressure Monitoring Systems (TPMS) are designed to monitor the airpressure inside of pneumatic tires on various types of vehicles.Therefore pressure sensors are used in the tires and the system mayreport the tire pressure information to the driver of the vehicle.Wireless transmission can be used to transmit information on thepressure data to a centralized receiver component in the vehicle. Such aconfiguration can enable the system to report or signal pressure lossesof the tires to the driver. Some known TPMS provide localizationinformation on the tire or wheel on top of pressure information so as toindicate to a driver of a vehicle the position of a wheel having apressure loss. Examples are indications on whether a pressure loss of atire of a wheel of a car is on the Front Left (FL) tire, the Front Right(FR) tire, the Rear Left (RL) tire, and/or the Rear Right (RR) tire.After replacement of a wheel or tire, assignment or re-assignment of thesensor signals to the positions on the vehicle may be necessary. Suchassignment can be carried out manually, for example, by using aLow-Frequency (LF) initializer, which is used to initialize eachindividual sensor upon indication from a system receiver. Theinitialization can be affected by sequentially activating anLF-initiator in the proximity of the respective sensor and receiving anaccording response with a unique identification from the sensor.

Some known TPMS systems utilize multiple LF-initializers, e.g. in termsof transmitter coils or inductors, for initialization of each individualsensor or wheel, for example, they can be mounted in the wheel housingof each wheel. The number of involved LF-initializers may render such anapproach uneconomic. For example, an identification of the sensor maythen be assigned to an initialized position on the vehicle, whichassumes that the according initialization procedure is carried outcorrectly after a change of tires, replacement of a wheel, etc. Otherconcepts make use of different reception levels of the LF-radio signalsusing transmitter coils at different locations asymmetric to the wheels,e.g. one in the front and one in the back. These concepts are extensiveand unsuitable for after-market installation. Further concepts make useof the varying reception power of the RF-signals transmitted by thesensors. The reception power of such an RF-signal can be measured andthe different locations can be distinguished by the different receptionlevels, e.g. evoked by different distances of the wheels. The larger thedistance between a wheel and the corresponding receiver the lower thereception power. In some cars a distinction between the signals from thefront and the signals from the back is possible, as the receiver islocated at an asymmetric position i.e. close to a rear axis, adistinction between signals from the left and right is rather difficult.Some concepts may use a set of acceleration sensors, which are installedin an orthogonal manner in each wheel to determine the rotationaldirection of the wheels to distinguish left and right wheels. Thisconcept may suffer from the complex propagation paths of the wirelesssignals, which may render an assignment of a reception level of a signalto a certain wheel difficult.

Another concept uses ABS (Anti-lock Braking System) signals to determinerotational frequencies of the wheels and relate or correlate them torotational frequencies determined based on TPMS signals, which may makeuse of acceleration sensors determining the acceleration changes as thesensor rotates with the wheel in gravitation. This concept, however, maybe difficult to establish if the signals of the ABS system cannot bemade available. This may render the concept unsuitable for after-marketsystems.

SUMMARY

Embodiments make use of information on a state of movement of a vehicle.In the following a vehicle can be any vehicle using tires, as, forexample, a car, a van, a truck, a bus, a plane, a bike, a motorbike,etc. Although, many embodiments will be exemplified using a car, anyother vehicle can be utilized in embodiments. The state of movement mayhave implications on the location and a state of a wheel. In thefollowing the state of movement of a vehicle refers to a movementstatus, a motion status, a driving or movement situation, a movement ordriving condition, etc., as for example, a forward movement, a backwardmovement, a movement along a right hand bend or curve, a movement alonga left hand bend or curve, etc.

Embodiments may provide a system for locating a position of a wheel on avehicle. The system may comprise a detector for obtaining informationrelated to the state of movement of the vehicle and a locator fordetermining the position of the wheel based on the information relatedto the state of movement of the vehicle. In further embodiments thelocator may be operable to further use information on a rotationalfrequency of the wheel to determine the position of the wheel based onthe information related to the state of movement of the vehicle.Embodiments may make use of the finding that a certain state of movementof a vehicle may imply a certain relation of the rotational frequenciesof the wheels. In other words, embodiments may make use of the findingthat the RR wheel of a car moving forward along a right hand bend mayhave a lower rotational frequency than any of the other wheels on thecar, assuming equal circumferences of the wheels. Therefore, if theinformation related to the state of movement indicates a forward righthand bend the locator may determine the position of the wheel beingindicated as the one with the lowest rotational frequency as the RRwheel.

In some embodiments the information related to the state of movement maycomprise information on a sense of a rotation of the vehicle. The senseof rotation of a vehicle may be used to determine expected rotationalfrequencies or expected relations of rotational frequencies of thewheels associated with the sense of rotation of the vehicle. In furtherembodiments the information related to the state of movement maycomprise information on a direction of the movement of the vehicle, e.g.information on whether the vehicle moves forward or backward, along aright hand bend or a left hand bend, etc. Information on the directionof the movement of the vehicle may also be used to determine expectedrotational frequencies or expected relations of rotational frequenciesof the wheels associated to the sense of rotation of the vehicle.

The locator may be operable to use information on rotational frequenciesfor each of a plurality of wheels on the vehicle, as, for example, fourwheels of a car. The locator may be further operable to determine aposition for each of the plurality of wheels on the vehicle based on theinformation on the plurality of rotational frequencies and theinformation related to the state of movement of the vehicle. In otherwords, the locator may determine predefined positions of the four wheelsof a car, by determining four rotational frequencies, one for each ofthe wheels, and by determining four expected rotational frequenciesbased on the information related to the state of movement. In someembodiments the locator or detector comprises an interface to receiveinformation on an expected rotational frequency from a device configuredto determine information related to one or more expected rotationalfrequencies of one or more wheels of a vehicle. That is to say,information related to the expected rotational frequencies may beprovided to the locator, which may then carry out a correlation betweenthe expected rotational frequencies and the rotational frequenciesdetermined from a sensor to determine one or more positions of thewheel(s). In some embodiments information related to rotationalfrequencies of one or more wheels of the vehicle may be provided to thedetector, e.g. as information related to a state of movement or relatedto a steering angle of the vehicle.

Hence, in further embodiments the locator may be operable to useinformation on rotational frequencies for each of the plurality ofwheels on the vehicle and to determine the position for each of theplurality of wheels on the vehicle based on the information on theplurality of rotational frequencies and the information related to thestate of movement of the vehicle. Moreover, the locator may be operableto assign predefined positions on the vehicle to each of the pluralityof wheels based on the information on the plurality of rotationalfrequencies and expected rotational frequencies, wherein the expectedrotational frequencies are based on the information related to the stateof movement, or information related to the expected rotationalfrequencies is obtained or received through an interface of the locatoror detector. In other words, embodiments may be based on the findingthat if the information on the state of movement indicates that a car asa vehicle moves forward along a right hand bend, then the expectedrotational frequency of the RR wheel is the lowest and that of the FLwheel is the highest. A correlation or a matching of the expectedrotational frequencies based on the information on the state of movementor the received information and the information on the rotationalfrequencies of the wheels may be carried out to determine the positionsof the wheels.

In an embodiment, the locator may be operable to sort the wheels basedon their rotational frequencies, to sort the predefined positions of thewheels based on the state of movement, or the information related to theexpected rotational frequencies, and a corresponding rotational velocityof the wheels, and to match the ranks of the sorted wheels and thesorted predefined positions.

Moreover, in embodiments the system or the detector may comprise asensor for determining the information related to the state of movement.The sensor may generate a signal based on which the information relatedto the state of movement can be determined. The sensor may correspond toat least one of an inertial sensor, a micro-mechanical sensor, anacceleration sensor, or a gyroscope for generating a signal based onwhich the state of movement is detectable. In some embodiments thesystem may further comprise an acceleration sensor, an energy harvester,a shock sensor, or a TPMS sensor to obtain the information on therotational frequency of the wheel.

The system may be operable to verify signals involved in the locationdetermination before actually determining the location or position of awheel, or before determining any signal based on which the locationshould be determined subsequently, respectively. In other words, thesystem may be operable to determine the location of the wheel or signalsbased on which the location of the wheel can be determined, when theinformation related to the state of movement of the vehicle indicates acertain state of movement. In some embodiments trigger information forthe location determination may be provided through an interface of thelocator. Furthermore, the system may determine the location of thewheels or the respective signals, only if the certain state of movementis maintained for a certain time period, when trigger information isreceived, respectively. In other words, in embodiments the system may beoperable to determine the location of the wheel or the respectivesignals only if a stable or an enduring state of movement has beendetected before, when trigger information is received, respectively.Thus, in embodiments the system may be operable to verify a signalindicating the rotational frequency of the wheel and a signal indicatingthe state of movement of the vehicle before using the signals asinformation to determine the position of the wheel. In yet anotherembodiment the system may be operable to verify whether the rotationalfrequency of the wheel and a rotational rate of the vehicle, which isbased on the state of movement of the vehicle, fulfill a predefinedrelation for a predefined time interval, e.g. their quotient has notbeen above or below a certain threshold. Thus, the locator may beoperable to determine the position of the wheel, when changes of thestate of movement of the vehicle have been below a predefined thresholdfor a predefined time interval, when trigger information is received,respectively.

In some embodiments the locator may comprise an interface to receiveinformation related to a trigger on when to determine the position. Thelocator may then be configured to determine the position of the wheelwhen the information related to the trigger is received. That is to saythat in some embodiments the time or state of the vehicle when todetermine the position of a wheel may be indicated to the locator, forexample, by a device configured to determine information related to oneor more expected rotational frequencies of one or more wheels of thevehicle. Details on such a device will be provided subsequently.

Furthermore, in embodiments the locator may be operable to determine acorrected rotational frequency of the wheel based on information on atire pressure of a tire of the wheel and based on the rotationalfrequency of the wheel. The locator may be operable to determine theposition of the wheel based on the corrected rotational frequency. Thus,if a tire pressure signal is available, the rotational frequency of awheel may be corrected based on the tire pressure signal. For thelocation determination the corrected signal may then be taken intoaccount.

In line with the above summary for embodying a system for locating aposition of a wheel on a vehicle, embodiments may provide a wheellocalizer for locating the position of the wheel on the vehicle. Thewheel localizer may comprise a detector with an output for a movementsignal comprising information on a state of movement of the vehicle. Inother words, the movement signal may comprise information related to thestate of movement of the vehicle. The wheel localizer further comprisesa locator with an input terminal for the movement signal, and an outputfor a location signal comprising information on the position of thewheel, which is based on the information on the state of movement of thevehicle.

Moreover, embodiments may provide a corresponding wheel localizationdevice, which comprises an input for receiving a signal comprisinginformation on the state of movement of the vehicle. Such a signal may,in some embodiments, be generated by a sensor. The input furtherreceives signals comprising information indicating rotationalfrequencies of each of a plurality of wheels of the vehicle, e.g. foreach of the four wheels of a car. In some embodiments accelerationsensors or TPMS sensors in the wheels or tires may be used to determinesignals based on which the rotational frequencies are determined. Theinput further receives signals comprising information indicating a tireparameter for each of the plurality of wheels, which may, in someembodiments, be TPMS signals from a TPMS sensor. The wheel localizationdevice further comprises a unit to assign to each of the plurality ofwheels one location of a set of predefined locations based on theinformation on the state of movement and the information on therotational frequencies.

Furthermore, embodiments may provide a method for locating a position ofa wheel on a vehicle. Such method may be part of a computer program insome embodiments. In other words, the computer program may have aprogram code for performing, when the computer program is executed on acomputer or on a processor, one of the methods described herein. Such amethod may comprise obtaining information related to a state of movementof the vehicle and determining the position of the wheel based on theinformation related to the state of movement of the vehicle.

Embodiments may also provide a device comprising a wheel localizer todetermine a position for each of a plurality of wheels of a vehicle. Thewheel localizer may be configured to determine a wheel position based oninformation indicating a rotational frequency of each wheel andinformation related to a rotation of the vehicle. The informationindicating the rotational frequency of the wheel may be determined froma signal, which is generated in the tire of the respective wheel. Insome embodiments such a signal may be generated using a TPMS sensor inthe respective wheel.

According to further embodiments, a correlation with information on asteering angle of the vehicle can be used to determine the position ofthe wheel. That is to say that the information on the state of movementmay correspond to information on a steering angle of the vehicle. Insuch an embodiment the system for locating a position of a wheel on avehicle may comprise a detector configured to obtain information relatedto a steering angle of the vehicle. Moreover the system may comprise alocator configured to determine the position of the wheel based on theinformation related to the steering angle of the vehicle. Theinformation related to the steering angle may determine the state ofmovement of the vehicle, e.g. whether it moves along a right hand bendor a left hand bend. The information related to the steering angle maycomprise further information related to a state of movement of thevehicle, e.g. whether the vehicle moves forward or backward or eveninformation on the speed or velocity of the vehicle.

The detector may comprise at least one of an angular sensor, a traversearm position sensor, an optical sensor, or a magnetic sensor, whereineach are configured to generate a signal based on which the steeringangle is detectable. In other words, the detector may comprise a sensor,which is capable of determining the information related to the steeringangle, for which there are multiple possibilities. For example, a signalfrom a power steering unit may be determined, e.g. using an angularsensor. In some embodiments, a signal, which is also used for anElectronic Stability Control (ESP), may be used for determining thesteering angle. A position of the steering wheel indicative of asteering angle may be monitored using a magnetic or an optical sensor,which may, for example monitor magnetic or optical checkmarks on thesteering wheel, a steering shaft or axis, or a steering column.

Another possibility is to determine the position of a traverse arm orother mechanical devices being coupled to a wheel. Therewith theposition of the traverse arm can be indicative of the position ororientation of the wheel and hence of a steering angle. Otherpossibilities arise from using an optical sensor, which can monitor awheel directly or any mechanical parts connected or coupled to thesteering, e.g. checkmarks on a steering axle or shaft, or on a traversearm. The locator may be configured to further use information on arotational frequency of the wheel to determine the position of the wheelbased on the information related to the steering angle in line with whatis described above. The locator may be configured to use information onrotational frequencies for each of a plurality of wheels on the vehicleand determine a position for each of the plurality of wheels on thevehicle based on the information on the plurality of rotationalfrequencies and the information related to the steering angle of thevehicle, also in line with what was described above.

Further in line with the above description the locator may be operableto assign predefined positions on the vehicle to each of the pluralityof wheels based on the information on the plurality of rotationalfrequencies and expected rotational frequencies, wherein the expectedrotational frequencies are based on the information related to thesteering angle and information related to a speed of the vehicle. Insome embodiments the information related to the speed of the vehicle mayindicate whether the vehicle is moving or not, in other embodiments itmay comprise information indicative of the actual speed of the vehicle.In other words, the locator may determine expected rotationalfrequencies based on the information on the steering angle andinformation on the speed of the vehicle, or it may receive informationrelated to expected rotational frequencies through an interface. In someembodiments just relations of the expected rotational frequencies may bedetermined, i.e. which wheel spins the fastest, second fastest, slowest,second slowest, etc. The same relations can then be determined from theplurality of rotational frequencies and matched with the expectedrelations. Therewith, the rotational frequencies can be assigned topredetermined positions of the wheels. In other embodiments more exactexpected rotational frequencies may be determined, e.g. also consideringthe geometrics of the vehicle, e.g. distances between the axis, betweenthe wheels, width of the vehicle/axis, length of the vehicle/axis, etc.

According to the above, the system may further comprise an accelerationsensor, an energy harvester, a shock sensor or a tire pressuremonitoring system sensor configured to obtain the information on therotational frequency of the wheel. A shock-sensor may determineacceleration changes, i.e. it may measure or determine a derivative ofthe acceleration with respect to time. The system may be operable toverify a signal indicating the rotational frequency of the wheel and asignal indicating the steering angle of the vehicle before using thesignals as information to determine the position of the wheel. Forexample, the system may be operable to verify that the rotationalfrequency of the wheel and a rotational rate of the vehicle, which canbe based on the steering angle of the vehicle, fulfill a predefinedrelation for a predefined time interval, accordingly. For example, thelocator is operable to determine the position of the wheel when changesof the steering angle of the vehicle are below a predefined thresholdfor a predefined time interval to assure a certain stability of theaccording signals or values, when the trigger information is receivedthrough the interface, respectively. Further in line with the abovedescribed embodiments the locator may be operable to determine acorrected rotational frequency of the wheel based on information on atire pressure of a tire of the wheel and based on the rotationalfrequency of the wheel, and the locator may be operable to determine theposition of the wheel based on the corrected rotational frequency.

In other words, embodiments may provide a wheel localizer for locating aposition of a wheel on a vehicle, which comprises a detector configuredto output a steering signal comprising information on a steering angleof the vehicle and a locator configured to receive the steering signal,and configured to generate a location signal comprising information onthe position of the wheel based on the information on the steering angleof the vehicle. The detector may comprise at least one of an angularsensor, a traverse arm position sensor, a magnetic sensor, or an opticalsensor, wherein each are configured to sense the steering angle of thevehicle. Further in line with the above, the locator may furthercomprise an input configured to receive a signal comprising informationon a rotational frequency of the wheel. At least one of a sensor, anangular sensor, a traverse arm position sensor, an optical sensor anacceleration sensor, an energy harvester, a shock sensor, or a tirepressure monitoring system sensor may be coupled to the locator. Thelocator may further comprise an input configured to receive a signalcomprising information related to a speed of the vehicle, which, in someembodiments, may only indicate that the vehicle is moving at all.

According to the above described embodiments the wheel localizer may befurther configured to verify a signal comprising information on therotational frequency of the wheel and the steering signal comprising theinformation on the steering angle of the vehicle, before using thesesignals as information to determine the position of the wheel. The wheellocalizer can be further configured to verify that the signal comprisingthe information on the rotational frequency of the wheel and thesteering signal comprising the information on the state of movement ofthe vehicle fulfill a predefined relation for a predefined timeinterval. The locator may comprise one or more inputs configured toreceive signals comprising information on a plurality of rotationalfrequencies for each of a plurality of wheels. The locator may beconfigured to determine a plurality of locations for the plurality ofwheels on the vehicle, based on the information on the plurality ofrotational frequencies and on the information of the state of movement.

The locator may be configured to assign predefined positions on thevehicle to each of the plurality of wheels based on the information onthe plurality of rotational frequencies and expected rotationalfrequencies, wherein the expected rotational frequencies are based onthe information of the steering angle. The locator may further comprisean input configured to receive a signal comprising information on a tirepressure of a tire of the wheel, and the locator may be operable todetermine a corrected rotational frequency of the wheel based on theinformation on the tire pressure of the tire of the wheel. The locatormay be operable to output the information on the location of the wheelbased on the corrected rotational frequency.

Embodiments further provide a wheel localization device, which comprisesan input configured to receive a signal comprising information on asteering angle of the vehicle, signals comprising information indicatingrotational frequencies of each of a plurality of wheels of the vehicle,and signals comprising information indicating a tire parameter for eachof the plurality of wheels. The wheel localization device may furthercomprise a unit configured to assign to each of the plurality of wheelsone location of a set of predefined locations based on the informationon the steering angle and the information on the rotational frequencies.Furthermore, embodiments may provide a method for locating a position ofa wheel on a vehicle. The method comprises obtaining information relatedto a steering angle of the vehicle and determining the position of thewheel based on the information related to the steering angle.

In embodiments the method may further comprise using information on arotational frequency of the wheel for the determining of the position ofthe wheel based on the information related to the steering angle. Theusing may comprise using information on rotational frequencies of aplurality of wheels on the vehicle, and the determining may comprisedetermining positions for each of the plurality of wheels on the vehiclebased on the information on the plurality of rotational frequencies andthe information related to the steering angle. The determining maycomprise assigning predefined positions on the vehicle to each of theplurality of wheels based on the information on the plurality ofrotational frequencies and expected rotational frequencies, whereexpected rotational frequencies can be based on the information relatedto the steering angle. The method may further comprise verifying asignal indicating the rotational frequency of the wheel and a signalindicating the steering angle of the vehicle, before using the signalsas information to determine the position of the wheel. The verifying mayverify that the rotational frequency of the wheel and a rotational rateof the vehicle, which is based on the steering angle of the vehicle,fulfill a predefined relation for a predefined time interval. The methodmay further comprise correcting the rotational frequency of the wheelbased on information on a tire pressure of a tire of the wheel todetermine a corrected rotational frequency. The determining of theposition of the wheel can be based on a corrected rotational frequency.Embodiments further provide a computer program having a program code ona non-transitory media for performing, when the computer program isexecuted on a computer or on a processor, one of the above methods forlocating a position of a wheel on a vehicle. In line with the above,some embodiment of the method may determine a position after receivinginformation related to a trigger for the location determination.

Embodiments further provide a device, which is configured to determineinformation related to one or more expected rotational frequencies ofone or more wheels of a vehicle. The device may be part of or comprisedin, for example, a navigation system, a smart phone, a handheldcomputer, a laptop, an entertainment system etc. The device comprises apath detector configured to determine expected path lengths of the oneor more wheels of the vehicle based on information related to a path ofthe vehicle. The device further comprises a controller configured todetermine the information related to the one or more expected rotationalfrequencies of the one or more wheels of the vehicle based on theexpected path lengths of the one or more wheels. The path detector maycorrespond to any module, unit, or device, which is configured todetermine, calculate or compute a length a wheel travels based on thepath or route of the vehicle itself. The controller may correspond toany module, unit, or device, which is configured to determine, compute,or calculate the information related to the one or more expectedrotational frequencies of the one or more wheels of the vehicle based onthe expected path lengths of the one or more wheels. The controller orpath detector may correspond to any controller module, unit or device,which may, at least in some embodiments be programmable, e.g. amicro-processor, a central processing unit, etc.

In some embodiments the path detector may obtain the path of the vehicleitself, e.g. by tracking or monitoring the vehicle. In embodiments thepath detector may comprise a Global Positioning System (GPS) receiver—orany other navigation unit. In some embodiments the device may furthercomprise a navigation module configured to determine the informationrelated to the path of the vehicle based on information related to aroute of the vehicle. The navigation module may comprise a GPS—or anyother navigation unit, which allows tracking, determining, or predictinga route or path of the vehicle. For example, the route may be entered bya user, e.g. in terms of a destination of a trip to which the actualroute is then determined or calculated based on navigational map data.In some embodiments a navigation system, comprising the abovecomponents, may determine the path lengths for one or more wheels of thevehicle based on the route or a part of the route of the vehicle andcorrelates the information related to corresponding rotationalfrequencies, respectively, with measured or otherwise determinedrotational frequencies, e.g. using the above described sensors, such asa TPMS sensor and the signals received therefrom. In some embodimentsthe controller is further configured to determine the informationrelated to the expected rotational frequencies of the one or more wheelsof the vehicle based on predefined geometry information of the one ormore wheels of the vehicle. The geometry information may compriseinformation related to, e.g., distances between the axis, between thewheels, width of the vehicle/axis, length of the vehicle/axis, etc.

For example, the information related to the rotational frequenciescomprises information related to an order of expected rotationalfrequencies or expected path lengths of a plurality of wheels of thevehicle. In some embodiments relations of the expected rotationalfrequencies may be determined, i.e. which wheel spins or rotates thefastest, second fastest, slowest, second slowest, etc. The samerelations can then be determined from the plurality of rotationalfrequencies obtained from, for example, the TPMS sensors and matchedwith the expected relations. Therewith, the rotational frequencies canbe assigned to predetermined positions of the wheels. In otherembodiments more exact expected rotational frequencies may bedetermined, e.g. also considering the geometrics of the vehicle, e.g.distances between the axis, between the wheels, width of thevehicle/axis, length of the vehicle/axis, etc.

In further embodiments the controller may be configured to determine oneor more positions of the one or more wheels of the vehicle based on theinformation related to the expected rotational frequencies of the one ormore wheels. Similar to the above, the controller may be configured tocorrelate the expected rotational frequencies with rotationalfrequencies, which are measured or determined using a sensor etc.Embodiments may enable an assignment of a position of a wheel to becarried out automatically, which may be more comfortable and lesserroneous than manually assigning after a wheel change or newinitialization of sensors. Embodiments may further enable to beretro-fitted to existing sensors, systems etc. That is to say that someembodiments may be adapted to existing systems. For example, embodimentsmay be integrated in a portable device, e.g. a smart phone or a portablenavigation system, which may then determine the positions and evendisplay the tire pressures.

In some embodiments, the controller may comprise an interface configuredto provide the information related to the one or more expectedrotational frequencies of the one or more wheels of the vehicle to asystem for locating a position of a wheel on a vehicle in line with theabove description. In some embodiment the interface may be configured toprovide information related to a trigger when to determine the positionof a wheel, also in line with the above description. In other words,based on the route of the vehicle and the differences in the pathlengths of the wheels or rotational frequencies of the wheels,advantageous points in time or moments for the localization of the wheelmay be determined, and information thereon may be provided as triggerinformation. The controller may be configured to provide the informationrelated to the trigger, when the expected rotational frequencies of theone or more wheels of the vehicle fulfill a predefined criterion. Forexample, the information related to the trigger may be provided when thedifferences of expected rotational frequencies or path lengths of thewheels of the vehicle differ by more than a predefined threshold.

In line with the above, in some embodiments the controller may comprisean interface configured to receive information related to one or moretire pressures of the one or more wheels of the vehicle. The interfacemay further be configured to receive information related to one or morerotational frequencies of the one or more wheels. The controller may beconfigured to associate the information related to the one or more tirepressures to one or more positions of the one or more wheels based onthe information related to the one or more rotational frequencies andbased on the information related to the one or more expected rotationalfrequencies of the one or more wheels of the vehicle. For example, thecontroller may correlate the path lengths or expected rotationalfrequencies with the information, e.g. a signal, related to the tirepressures, which may comprise information related to measured rotationalfrequencies of the one or more wheels. For example, the wheel with thelongest path lengths or highest expected rotational frequency may beassociated with the wheel having the highest measured rotationalfrequency; the wheel with the second longest path lengths or secondhighest expected rotational frequency may be associated with the wheelhaving the second highest measured rotational frequency and so on.

The path detector may be configured to determine an expected pathlengths for each of a plurality of wheels on the vehicle based on theinformation related to the path of the vehicle. The controller may beconfigured to determine information related to an expected rotationalfrequency for each of the plurality of wheels on the vehicle. Forexample, the vehicle may have four wheels and the path detector maycorrespondingly determine four path lengths and the controller maycorrespondingly determine four expected rotational frequencies. Thecontroller may be configured to determine a position for each of theplurality of wheels on the vehicle based on the information on theplurality of expected rotational frequencies and based on the expectedpath lengths for each of the plurality of wheel of the vehicle. Forexample, four positions for four wheels of the vehicle may bedetermined. In some embodiments the controller may be configured toassign predefined positions on the vehicle to each of the plurality ofwheels based on the information on the plurality of expected rotationalfrequencies. For example, the above described correlation may be used.Such correlation may be based on a ranking of the paths lengths orexpected rotational frequencies and an according ranking of the measuredrotational frequencies, e.g. on the basis of sensor signals.

In some embodiments the device may comprise an interface configured toreceive information related to tire pressures for each of the pluralityof wheels of the vehicle. The interface may be further operable toreceive information related to a rotational frequency for each of theplurality of wheels of the vehicle, which may correspond to measuredrotational frequencies, in line with the above description. Thecontroller may be configured to associate the information on the tirepressures to positions of each of the plurality of wheels based on theinformation related to the rotational frequency for each of theplurality of wheels and based on the information related to the expectedrotational frequency for each of the plurality of wheels of the vehicle.

Embodiments further provide a method for determining information relatedto one or more expected rotational frequencies of one or more wheels ofa vehicle. The method comprises determining expected path lengths of theone or more wheels of the vehicle based on information related to a pathof the vehicle. The method further comprises determining the informationrelated to the one or more expected rotational frequencies of the one ormore wheels of the vehicle based on the expected path lengths of the oneor more wheels. The method may further comprise determining theinformation related to the path of the vehicle based on information on aroute of the vehicle. In line with the above, the method may comprisedetermining the information related to the expected rotationalfrequencies of the one or more wheels of the vehicle based on predefinedgeometry information of the one or more wheels of the vehicle.

In some embodiments the information related to the rotationalfrequencies comprises information related to an order of expectedrotational frequencies of a plurality of wheels of the vehicle. Themethod may comprise determining one or more positions of the one or morewheels of the vehicle based on the information related to the expectedrotational frequencies of the one or more wheels. According to theabove, the method may comprise receiving information related to one ormore tire pressures of the one or more wheels of the vehicle andreceiving information related to one or more rotational frequencies ofthe one or more wheels. The method may comprise associating theinformation on the one or more tire pressures to one or more positionsof the one or more wheels based on the information related to the one ormore rotational frequencies and based on the information related to theone or more expected rotational frequencies of the one or more wheels ofthe vehicle.

The method may comprise determining a path length for each of aplurality of wheels on the vehicle based on the information related tothe path of the vehicle. Information related to an expected rotationalfrequency for each of the plurality of wheels on the vehicle may bedetermined. A position for each of the plurality of wheels on thevehicle may be determined based on the information on the plurality ofexpected rotational frequencies and based on the path lengths for eachof the plurality of wheels of the vehicle. The method may furthercomprise assigning predefined positions on the vehicle to each of theplurality of wheels based on the information on the plurality ofexpected rotational frequencies. Corresponding to the above, the methodmay further comprise receiving information related to tire pressures foreach of the plurality of wheels of the vehicle, and receivinginformation related to a rotational frequency for each of the pluralityof wheels of the vehicle. The method may comprise associating theinformation on the tire pressures to positions of each of the pluralityof wheels based on the information related to the rotational frequencyfor each of the plurality of wheels and based on the information relatedto the expected rotational frequency for each of the plurality of wheelsof the vehicle.

Embodiments further provide a computer program having a program code ona non-transitory media for performing, when the computer program isexecuted on a computer or on a processor, a method for determininginformation related to one or more expected rotational frequencies ofone or more wheels of a vehicle. The method comprises determiningexpected path lengths of the one or more wheels of the vehicle based oninformation related to a path of the vehicle. The method furthercomprises determining the information related to the one or moreexpected rotational frequencies of the one or more wheels of the vehiclebased on the expected path lengths of the one or more wheels.

An advantage of embodiments may be that information on the state ofmovement of the vehicle can be used to determine expected rotationalfrequencies of the wheels. Embodiments may therefore be independent fromother systems such as ABS. Moreover, embodiments may localize a wheel ona vehicle without utilizing LF-initializers, and without determining RFreception levels. Embodiments may therefore be more cost effective, evencompared to concepts using one asymmetric LF-transmitter per axis, e.g.one in the front and one in the back, making use of differentLF-reception levels at the receivers.

It may be an advantage of embodiments that a comparison of rotationalfrequencies of other systems, such as ABS, may be circumvented. Thesesystems may utilize information on a rotational frequency of each wheelat a centralized receiver. The information on the rotational frequenciesmay then be compared to the rotational frequencies of the ABS system.For some determined driving situations different rotational frequenciesresult and the correlation of the rotational frequencies determinedthrough ABS and another sensor may be used to find the respectivepositions of the wheels. The determination of the rotational frequencymay be a function of the TPMS module in the wheels. Embodiments mayovercome the disadvantage of such systems, accessing the ABSinformation, which are conceivable in Original Equipment Manufacturer(OEM) systems, where a TPMS and an ABS system are provided or developedby the same tier. If TPMS and ABS are developed in separate tiers, for aconventional system a need for a standardized interface arises andadditional connection or wiring may be necessary. Moreover, the ABSsignal would have to be adapted to the correlation with respect to itsdata rate and its downtimes. Therefore, embodiments provide theadvantage that they may not rely on ABS' or other capsulated system'ssignals and are therefore better suitable for after-marketimplementations.

Embodiments may enable a retro-fit application to existing systems. Forexample, an according device may be portable (phone, navigation/GPSsystem) and mounted into a vehicle using existing signal and/or sensorimplementations. Some embodiments may correspond to a computer program,such as a loadable application, and may be installed to accordingprogrammable hardware. Some embodiments may communicate with a sensor orreceive information from a sensor, such as a TPMS sensors installed on avehicle, e.g. using an accordingly configured interface. For example, 4TPMS modules may communicate with a receiver, which may, for example, bepowered by a lighter plug in a car. The receiver may receive sub 1 GHzsignals from the TPMS modules and may provide information related to theTPMS signals to an embodiment of a device, e.g. using Bluetooth. Theembodiment of the device may correspond to a smart phone or navigationsystem and may display the tire pressures assigned to the positions ofthe corresponding wheels. The positioning of the tire pressureinformation to the corresponding wheel may be enabled automaticallyaccording to the above described embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Some other features or aspects will be described using the followingnon-limiting embodiments of apparatuses and/or methods and/or computerprograms by way of example only, and with reference to the accompanyingfigures, in which

FIG. 1 a shows an embodiment of a system for locating a position of awheel;

FIG. 1 b shows an embodiment of a device configured to determineinformation related to one or more expected rotational frequencies;

FIG. 2 shows four wheels of a vehicle, which are positioned in anembodiment;

FIG. 3 shows four wheels of a vehicle, which are positioned in anembodiment, from an overview perspective depicting the differences inthe travel distances of the wheels;

FIG. 4 depicts the dependency of the angle between the wheels and thesteering angle;

FIG. 5 illustrates an embodiment of a wheel localizer;

FIG. 6 illustrates an embodiment of a wheel localization device;

FIG. 7 shows a flow chart of an embodiment of a method for locating aposition of a wheel on a vehicle; and

FIG. 8 shows a flow chart of an embodiment of a method for determininginformation related to one or more expected rotational frequencies ofone or more wheels of a vehicle.

DETAILED DESCRIPTION

In the following some components will be shown in multiple figures,where consistent reference signs refer to functionally identical orsimilar components. Repetitive descriptions may be avoided forsimplicity purposes. Features or components depicted in dotted lines areoptional.

FIG. 1 a shows an embodiment of a system 100 for locating a position ofa wheel on a vehicle. The system 100 comprises a detector 110 forobtaining information related to a state of movement of the vehicle, anda locator 120 for determining the position of the wheel based on theinformation related to the state of movement of the vehicle. Theinformation on the state of movement may correspond to informationrelated to a steering angle of the vehicle. The locator 120 may beoperable to further use information on a rotational frequency of thewheel to determine the position of the wheel based on the informationrelated to the state of movement or to the steering angle of the vehicleas indicated by the dotted arrow in FIG. 1 a.

The information on the rotational frequency of the wheel may be obtainedusing an acceleration sensor, which may be further comprised in thesystem 100. The acceleration sensor may be installed on the wheel suchthat a sensitive axis of the acceleration sensor has a radialorientation. Hence it senses a change in the acceleration of gravitywhen the wheel turns, in particular a +/−g change.

In other embodiments, TPMS sensors may be used to determine theinformation on the rotational frequency of the wheel. A TPMS sensor maybe mounted on the cover of the tire such that a g-pulse is measured whenthe TPMS sensor hits the surface of the road. An acceleration sensor maybe used in the TPMS sensor, e.g. for that purpose. The TPMS sensor maybe equipped with an energy harvester or a nano generator, e.g. as theyare used in battery-free TPMS sensors, which convert the mechanicalenergy of the pulse when the TPMS sensor hits the ground into anelectrical signal from which the information on the rotational frequencyof the wheel can be determined. In further embodiments the system mayuse an acceleration or shock sensor to determine the information on therotational frequency of the wheel, e.g. by making use of gravity. Yetanother embodiment of the system may comprise a TPMS sensor to obtainthe information on the rotational frequency of the wheel by evaluatingthe cyclic variations of the TPMS-RF signals.

In the embodiment depicted in FIG. 1 a the locator 120 is operable touse information on rotational frequencies for each of a plurality ofwheels on the vehicle, e.g. the four wheels of a car. Moreover, thelocator 120 is operable to determine a position for each of theplurality of wheels on the vehicle based on the information on theplurality of rotational frequencies and the information related to thestate of movement of the vehicle, the information related to thesteering angle, respectively. In other words, the system 100 may usemultiple sensors for the determination of the rotational frequencies ofthe wheels, e.g. it may use one sensor per wheel.

The system 100, and also the device 500, which will be described in thesequel, illustrated in FIG. 1 a, FIG. 1 b, respectively, may form anautonomous system for locating the wheel, which is independent fromother systems such as ABS, and other data from the vehicle. Theindependence can be achieved by using the information related to thestate of movement or the steering angle of the vehicle, which maycomprise information on a sense of a rotation of the vehicle and/orinformation on a direction of movement of the vehicle. The system 100 orthe detector 110 may detect the information on the state of movement orthe information related to the steering angle of the vehicle based on acorresponding sensor. In other embodiments information on the state ofmovement or on expected rotational frequencies may be received from adevice 500. Such information may be in terms of different path lengthsor expected rotational frequencies of one or more wheels. The system100, the detector 110, or the locator 120 may comprise an accordinglyconfigured interface to receive information related to path lengths orexpected rotational frequencies. For example, the system 100 or thedetector 110 may comprise an inertial sensor, which enablesdetermination of the information related to the state of movement of thevehicle. Additionally or alternatively, the detector may comprise or usea magnetic sensor, which senses a signal from a power steering. Thesensor may sense the position of magnetic checkmarks on a steeringcolumn or axis of the vehicle. Such a sensor may also be used for otherfunctionalities such as ESP in the vehicle.

In other embodiments the system 100 or the detector 110 may comprise amicro-mechanical sensor (Micro-Electro-Mechanical Systems (MEMS)), anacceleration sensor, or a gyroscope for generating a signal based onwhich the state of movement is detectable. The inertial sensor maycorrespond to a rotation rate sensor or a combination of a rotation ratesensor and a single- or multi-axial acceleration sensor. A sensitiveaxis of the rotational rate sensor may be oriented basically orthogonalto a movement plane of the vehicle, such that the sensor can be used asyaw-sensor. In embodiments, the inertial sensor may not be located in awheel but at a more central position, e.g. in the receiver for theTPMS-RF signals. Therefore, any additional power consumption evoked bythe inertial sensor may not be relevant in embodiments; such additionalpower consumption may range at about 5 mA.

It is to be noted that in embodiments the absolute accuracy of such aninertial sensor may not be very high. As the sensor may only be used todetermine a certain state of movement or a movement situation, e.g. acertain rotational rate or directional movement of the vehicle. In otherwords, a certain state of movement may be determined before thelocalization of the wheel is carried out. Since the accuracy orprecision demands for the sensor are low, embodiments of the system 100can be economically implemented. For example, a MEMS inertial sensor maybe used, as it is produced in high numbers for other applicationsalready.

Thus, an algorithm for localizing the wheel may be carried out in acertain state of movement of the vehicle; it may be carried out based onsignals obtained in the certain state of movement of the vehicle,respectively. In other words, the detector 110 may use the inertialsensor to determine whether the vehicle moves along a left hand bend oralong a right hand bend. Moreover, the detector 110 may determinewhether the vehicle moves in a forward or in a backward direction. Forexample, a comparison of the rotational frequencies of the wheels withthe rotational rate of the vehicle may determine or trigger an operatingpoint for the localization. In some embodiments such trigger informationmay be received from a device 500. The detector 110, the locator 120,respectively, may then comprise an accordingly configured interface toreceive the information. Thus, in embodiments the system 100 may also beoperable to verify a signal indicating the rotational frequency of thewheel and a signal indicating the state of movement or the steeringangle of the vehicle before using the signals as information todetermine the position of the wheel. For example, the system 100 may beoperable to verify that the rotational frequency of the wheel and arotational rate of the vehicle, which is based on the state of movementor the steering angle of the vehicle, fulfill a predefined relation fora predefined time interval. In embodiments such verification may becarried out using different mechanisms. According to another embodiment,the locator 120 is operable to determine the position of the wheel whenchanges of the state of movement or the steering angle of the vehicleare below a predefined threshold for a predefined time interval. That isto say, the position of the wheel is determined when the state ofmovement or a steering angle of the vehicle is stable to a certainextent, e.g. when variations of a certain rotational rate or steeringangle of the vehicle and the rotational frequencies of the wheels remainin certain boundaries.

The locator 120 may then assign predefined positions on the vehicle toeach of the plurality of wheels based on the information on theplurality of rotational frequencies and on expected rotationalfrequencies, wherein the expected rotational frequencies are based onthe information related to the state of movement or the steering angle.In line with what is described above, in some embodiments the sense ofmovement, i.e. whether the vehicle moves forward or backward and whetherit rotates clockwise or counterclockwise, serves as basis for thelocalization and an inertial sensor may be used to generate a signalbased on which the sense of movement is determined. In some embodimentsthe steering angle may be used. Other embodiments may use other means todetermine the state or sense of movement. For example, in someembodiments other signals available from the vehicle may be used. Forexample, an indication on whether the vehicles moves forward or backwardmay be obtained from the transmission components, such as an indicationfor a reversing or back-up light. Moreover, signals from a powersteering unit may be used to determine whether the vehicle steerstowards a right hand bend or a left hand bend. The steering angle can bedetermined from such a power steering unit.

Furthermore, the information on rotational frequencies of the wheels maybe used to determine information related to the state of movement or thesteering angle. For example, if a certain rotational frequency isexceeded, e.g. a certain threshold for the rotational frequency, it maybe assumed that the vehicle moves forward, as the backward speed of mostvehicles is limited. A comparison of the minimum and maximum rotationalfrequencies of all tires may determine whether the vehicle moves along abend since the tires closer to a center of a bend or curve rotate slowerthan tires farther away from the center of the curve. As will be shownin more detail subsequently, if a vehicle moves through a given bend,certain rotational rates or relations of the rotational rates result forits wheels.

In some embodiments a backward movement of the vehicle may be precludedusing other measures as described above. In such an embodiment arotational sensor with a single axis can be used to determine a signalbased on which the information related to the state of movement isdetected. The sensitive axis of such a sensor may then be oriented inparallel to the normal (z-axis) of the plane of movement of the vehicle.When the vehicle moves along a right hand bend the rotational sensor mayprovide a negative output signal, a positive output signal may result ina left hand bend. Backward movement may be precluded by determining acertain duration of such a signal, since long time backward movementsare unlikely.

In some embodiments, determination or preclusion of a backward movementmay be used to determine the sense of rotation of the vehicle. Forexample, a forward movement along a right hand bend may result in thesame sense of rotation as a backward movement along a left hand bend.The determination or preclusion of the backward movement may then beused to distinguish the right and left hand wheels of the vehicle.

In order to distinguish four different states of movement using acombined sensor comprising a rotational rate sensor and a lateralacceleration sensor may be used as an inertial sensor in a particularembodiment. The sensitive axis of the acceleration sensor corresponds tothe lateral axis of the vehicle (y-axis), i.e. to the axis pointing inthe radial direction when the vehicle moves along a bend or curve. Theoutputs of the two sensors are given by the following table:

Driving situation, state of Rotational rate Acceleration movement sensorsensor Forward, right hand bend Negative negative Forward, left handbend Positive positive Backward, right hand bend Positive negativeBackward, left hand bend Negative positive

The table shows that a non-ambiguous distinction of the four states isenabled using the combined sensor. In a similar way the drivingsituation or the state of movement may be determined from the steeringangle. If the steering angle is to the left the vehicle moves along aleft hand bend, if the steering angle is to the right the vehicle movesalong a right hand bend. Embodiments may make use of the finding thatthe rotational frequencies of the wheels, e.g. of the four wheels of acar, differ by multiple percent especially when the vehicle moves alongnarrow curves or bends. This assumption is based on a further assumptionthat the circumference or the perimeter of the wheels is essentiallysimilar. Some embodiments may assume that the localization of the wheelsis carried out directly after a change of the wheels and that the airpressure in the tires of the wheels corresponds to a set pressureaccording to the respective manufacturer's requirements. This leads tothe conclusion that the circumferences of the tires are essentiallyequal. Other embodiments may assume that the air pressure of all tiresand their circumferences are the same.

Yet other embodiments may use TPMS signals to correct the information onthe rotational frequencies. In other words, such embodiments maydetermine the rotational frequency of a wheel and the corresponding airpressure in the tire of the wheel. If the air pressure differs from apredefined air pressure setting for the wheel, the rotational frequencymay be corrected accordingly, i.e. if the air pressure is too low acorrected rotational frequency may be increased, or decreased if the airpressure of the tire is too high. In other words, the locator 120 may beoperable to determine a corrected rotational frequency of the wheelbased on information on a tire pressure of a tire of the wheel and basedon the rotational frequency of the wheel. The locator 120 may then beoperable to determine the position of the wheel based on the correctedrotational frequency. Moreover, it is assumed that each wheel or sensorprovides its signal together with a non-ambiguous IDentification (ID),such that each signal can be unambiguously associated to the respectivewheel or sensor.

The algorithm of an embodiment may then comprise the following. Atfirst, a reference wheel (unique ID) may be selected and based on therotational frequency of the reference wheel and the rotational rate orthe steering angle of the vehicle an advantageous operating point orstate of movement of the vehicle is determined. Once the operating pointis reached, the rotational frequencies of the four wheels are determinedand compared. For a given state of movement or steering angle, e.g. aforward right hand bend, the relations of the rotational frequencies ofthe wheels are predetermined, e.g. which wheel has the highest and whichwheel has the lowest rotational frequency. Thus expected rotationalfrequencies or relations thereof may be determined based on the state ofmovement or the steering angle. Each of the four wheels may then beassociated with a respective position, e.g. by matching the expectedrotational frequencies with the detected rotational frequencies of thewheels. The rotational rate and direction of movement of the vehicle maybe determined based on signals which were measured by the inertialsensor or from signals being indicative of the steering angle of thevehicle. In some embodiments the procedure just described may berepeated until a certain statistical confidence is achieved.

FIG. 1 b shows an embodiment of a device 500 configured to determineinformation related to one or more expected rotational frequencies,which may in some embodiments be used to determine the above informationrelated to the state of movement of the vehicle. The device 500comprises a path detector 510 configured to determine expected pathlengths of the one or more wheels of the vehicle based on informationrelated to a path of the vehicle. The device 500 further comprises acontroller 520 configured to determine the information related to theone or more expected rotational frequencies of the one or more wheels ofthe vehicle based on the expected path lengths of the one or morewheels. As shown in FIG. 1 b the device 500 may optionally comprise anavigation module 530 configured to determine the information related tothe path of the vehicle based on information related to a route of thevehicle.

In the following an embodiment will be described, wherein the controller520 is further configured to determine the information related to theexpected rotational frequencies of the one or more wheels of the vehiclebased on predefined geometry information of the one or more wheels ofthe vehicle, as will be further detailed subsequently usingillustrations shown in FIG. 2. FIG. 2 illustrates the four wheels of avehicle in an embodiment. FIG. 2 shows two front wheels FL and FR, aswell as two rear wheels RL and RR. Moreover, in the illustration of FIG.2 it is assumed that the vehicle moves along a forward right hand bend,where the center of the bend or curve is indicated by C. The angle ofthe front wheels FL and FR indicates movement along the right hand bend.It is further assumed that the distance between left and right wheels isS, i.e. the distance between FL and FR, as well as between RL and RR,respectively. Moreover, the distance between front and rear wheels isassumed to be L, i.e. the distance between FL and RL, between FR and RR,respectively. FIG. 2 further depicts the radii of each of the wheels andthe curve or trajectory itself using different arrows. The radius of thecurve or bend itself is labeled RC, the radius of the RR wheel is termedRRR, the radius of the RL wheel is termed RRL, the radius of the FLwheel is termed RFL, and the radius of the FR wheel is termed RFR.Furthermore, the trajectory of the FR wheel is given using a dottedarrow, which points along a circular segment. Furthermore, if the pathsof a vehicle, e.g. whether it moves through right hand or left handbend, the path lengths of each of its wheel may be determined. Thedepicted geometry allows determining the radii of each wheel and henceinformation on the path lengths of the individual wheel, at least of arelation between the path lengths of the wheels.

The geometry of the vehicle shown in FIG. 2 allows deriving expectedrotational frequencies of wheels and relations thereof based on thedistances L, S, and RC, the path of the vehicle, respectively. As it canbe seen from FIG. 2 each of the wheels travels along a different radius(RRR, RRL, RFL, RFR) around the center C of the curve, resulting indifferent distances, and thus in different rotational frequencies, whenequal circumferences for the wheels are assumed. The velocity of eachwheel is then proportional to the radius of the wheel's trajectory, toits rotational frequency, respectively. Moreover, the shorter the radiusof the curve, i.e. the narrower the curve, the higher the difference inthe individual radii (RRR, RRL, RFL, RFR). The radii can be given usingthe following equations:

${{RRL} = {{RC} + \frac{s}{2}}},{{RRR} = {{RC} - \frac{s}{2}}},{{RFL} = \sqrt{L^{2} + ( {{RC} + \frac{s}{2}} )^{2}}},{and}$${RFR} = {\sqrt{L^{2} + ( {{RC} - \frac{s}{2}} )^{2}}.}$

The equations show that the difference in the rotational frequencies ofthe wheels depends on the radius RC of the curve itself (the path of thevehicle), the wheel base L, and the wheel track S. FIG. 3 shows fourwheels (FR, RR, FL, RL) of a vehicle, which are positioned in theembodiment. The overview perspective depicts the differences in thetravel distances of the wheels. From FIG. 3 it can be seen that the fourwheels travel different distances when the vehicle moves along a bend asthey travel along circles with different diameters and hence withdifferent circumferences. The relative differences in the distancesdepend on the steering angle, which determines the radii of the circles.According to some embodiments the steering angle, the path of thevehicle, the velocity of the vehicle or the differences in the traveldistances of the wheels and/or the geometry of the vehicle (wheel base,track gauge, size of the tires) may serve as a basis for determiningexpected rotational frequencies or at least an order of expectedfrequencies of the wheels of the vehicle. With the signals of anTPMS-sensor, which comprises an acceleration sensor and sensesacceleration changes while rotating in gravitation, the rotationalfrequencies of the wheels and hence the order of them, can be determinedas well. Correlating or matching these signals or their order thenallows assignment of a TPMS-signal to the respective wheel and hencetheir positions.

In some embodiments the information related to the rotationalfrequencies comprises information related to an order of expectedrotational frequencies or expected path lengths of a plurality of wheelsof the vehicle, which may then be used for an according correlation. Thecontroller 520 of the embodiment illustrated in FIG. 1 b may beconfigured to determine one or more positions of the one or more wheelsof the vehicle based on the information related to the expectedrotational frequencies of the one or more wheels, e.g. using theabove-described correlation. The controller 520 may optionally comprisean interface 540 configured to provide the information related to theone or more expected rotational frequencies of the one or more wheels ofthe vehicle to a system 100 for locating a position of a wheel on avehicle. The interface 540 may be configured to provide informationrelated to a trigger when to determine the position of a wheel and thecontroller 520 may be configured to provide the information related tothe trigger, when the expected rotational frequencies of the one or morewheels of the vehicle fulfill a predefined criterion, for example, whendifferences of path lengths or expected rotational frequencies lie abovea predefined threshold. Accordingly, the above described detector 110 orlocator 120 may comprise an interface to receive information on anexpected rotational frequency from the device 500 configured todetermine information related to one or more expected rotationalfrequencies of one or more wheels of the vehicle. The locator 120 maythen use the information on the expected rotational frequencies for anaccording correlation.

In some embodiments the controller 520 may comprise an interface 540configured to receive information related to one or more tire pressuresof the one or more wheels of the vehicle. The interface 520 may befurther configured to receive information related to one or morerotational frequencies of the one or more wheels, for example, from oneof the above described sensors or from the detector 110 or locator 120,respectively. An according correlation may then be carried out by thecontroller 520. For example, the controller 520 may be configured toassociate the information related to the one or more tire pressures toone or more positions of the one or more wheels based on the informationrelated to the one or more rotational frequencies and based on theinformation related to the one or more expected rotational frequenciesof the one or more wheels of the vehicle.

Embodiments may enable to position or locate positions of signalsreceived from TPMS sensors. The path detector 510 may be configured todetermine an expected path length for each of a plurality of wheels onthe vehicle based on the information related to the path of the vehicle.The controller 520 may be configured to determine information related toan expected rotational frequency for each of the plurality of wheels onthe vehicle, and the controller 520 may be configured to determine aposition for each of the plurality of wheels on the vehicle based on theinformation on the plurality of expected rotational frequencies andbased on the expected path lengths for each of the plurality of wheelsof the vehicle. For example, the controller 520 may be configured toassign predefined positions on the vehicle to each of the plurality ofwheels based on the information on the plurality of expected rotationalfrequencies.

In some embodiments the device 500 may comprise an interface configuredto receive information related to tire pressures for each of theplurality of wheels of the vehicle. The interface may be furtheroperable to receive information related to a rotational frequency foreach of the plurality of wheels of the vehicle. The controller 520 maybe configured to associate the information on the tire pressures topositions of each of the plurality of wheels based on the informationrelated to the rotational frequency for each of the plurality of wheelsand based on the information related to the expected rotationalfrequency for each of the plurality of wheels of the vehicle.

For example, a navigation system may comprise the device 500, whichdetermines the differences in the path lengths of the wheels. The device500 may select a vehicle path in which the differences in path length ortravel distances of the wheel are significant enough to enable cleardistinction of the wheels by their path lengths or rotationalfrequencies. For example, a motorway junction or interchange may have atypical diameter of 60 m, which may lead to differences in path lengthsbetween inner and outer wheels in the bend or curve of about 5%. Arotary intersection or a roundabout with diameter of 15 m may providedifferences of about 20%. In some embodiments a TPMS-sensor may transmittire pressure information in equidistant time intervals to a receiver,the rotational frequency of the wheel may be determined based on thesesignals or the signal may comprise information related to the rotationalfrequency already determined by the TPMS-sensor. In some embodiments theTPMS-sensor may provide tire pressure information after a predeterminednumber of wheel rotations, which allows determining information on therotational frequency or the path length of a wheel from the time betweensubsequent provisions of the tire pressure information. Information onthe rotational frequency of a wheel may hence be determined from thetire pressure signals and may then be correlated with the expectedrotational frequencies to locate the corresponding tire on the vehicle.

FIG. 3 displays an example of a vehicle travelling along a left handbend. The trajectories of the wheels correspond to circles and they showthat the wheel closest to the center of the bend or curve, i.e. wheel RLtravels the shortest distance, followed by wheel FL, which travels thesecond shortest distance. The wheel FR, which is located the farthestaway from the center, travels the longest distance and wheel RR travelsthe second farthest distance and lies between the wheels FR and FL. FIG.3 further shows that the differences between the radii of the wheelclosest to the center and the wheel farthest from the centerapproximately matches the wheel base of the vehicles, whichapproximately may, for example, correspond to 1.5 m.

FIG. 4 depicts the dependency of the angle between the wheels and thesteering angle. As the rear axis of the vehicle depicted in FIG. 4 isassumed to be non-steered, i.e. it points along the radius of the bend,the relation between radii of the FL wheel and the RL wheel correspondto the cosine of the angle φ, which also corresponds to the steeringangle. In line with the Figures, the distances or rotational frequenciesof the wheels can be determined from the geometric evaluations. Inembodiments a TPMS-sensor may provide the TPMS-signals in regular timeframes, i.e. the signals with information related to the pressure of thetires may be transmitted on a fixed time frame, such as every 1 s, 2 s,5 s, 10 s, 15 s, 20 s, 25 s, 1 min, etc. In such embodiments aTPMS-sensor may transmit information on the rotational frequency of thewheel along with the pressure information. For example, the number ofrotations of the wheel since the last transmission or a presentrotational frequency may be included. In other embodiments such signalsmay be transmitted on a rotational frame basis. That is to say that theTPMS sensor may transmit the pressure signal every predefined number ofrotations, such as every 3, 5, 10, 15, 20, 25, 50, etc. rotations. Fromthe time between two or more transmissions of the pressure signals of awheel, the locator may conclude on the rotational frequency. In otherwords, the time span between two transmissions of the pressure signalfor a wheel is indicative of the distance the wheel traveled since thelast transmission. In both cases the determined data can be correlatedwith the data determined based on the state of movement or the steeringangle as basis for the positioning of the respective wheels.

Considering the geometry of a typical compact car, e.g. a VolkswagenGolf, and different radii RC of the curve the following table can becalculated using the above equations and using the RR wheel as areference. A forward movement along a right hand curve yields:

Radius of the Curve Relative rotational frequency with respect to RR RCRR FR RL FL [m] [%] [%] [%] [%] 5.0 0.00 14.54 26.69 33.03 7.5 0.00 6.5818.62 22.29 10.0 0.00 3.66 14.30 16.64 15.0 0.00 1.59 9.77 10.94 20.00.00 0.88 7.41 8.12 25.0 0.00 0.56 5.98 6.44

The table shows that the relative difference in the rotationalfrequencies increases with decreasing radius RC of the curve or bend,and so do the travel distances of the wheels, respectively. Therefore,some embodiments may determine a movement along a narrow curve as anoperating point. In other words, in some embodiments it is verified thatthe vehicle moves along a narrow curve before determining the rotationalfrequencies based on which the wheels are positioned. Determination ofsuch an operating point may therefore correspond to the determination ofa small radius RC of the curve. In some embodiments a measurement of therotation rate of the vehicle may not be sufficient, since a fastmovement along a curve or bend with a large radius may result in thesame rotational rate for the vehicle as a slow movement along a curve orbend with a small radius. Some embodiments may therefore evaluate aquotient of the rotational frequency of a reference wheel and therotational rate for the vehicle, which is proportional to the radius ofthe curve and may therefore support the determination of a properoperating point, the travel distances of the wheels, respectively.

As it has already been mentioned above in embodiments it may first beverified that the signals or frequencies which are used for such acomparison are stable to certain extent. For example, a certain timeperiod may be evaluated during which variations of the respectivesignals are below a threshold. Embodiments may therefore prevent errorsor deviations, which could occur when the vehicle moves along a sinuousline at a higher speed. In implementations of embodiments, advantageousranges for the rotational frequencies of the wheels and the rotationalrate of the vehicle may be determined experimentally.

Embodiments may also provide a device comprising a wheel localizer todetermine for each of a plurality of wheels of a vehicle a position, thewheel localizer being configured to determine a wheel position based oninformation indicating a rotational frequency of each wheel andinformation related to a rotation of the vehicle or a steering angle ofthe vehicle.

In embodiments the system 100 of FIG. 1 a may be implemented as a wheellocalizer 200 for locating a position of a wheel on the vehicle. FIG. 5illustrates an embodiment of a wheel localizer 200. The wheel localizer200 comprises a detector 210 with an output 212 for a movement orsteering signal comprising information on a state of movement or asteering angle of the vehicle. The detector 210 may correspond to theabove described detector 110. The wheel localizer 200 further comprisesa locator 220 with an input terminal 222 for the movement signal or asteering angle signal, and an output 224 for a location signalcomprising information on the position of the wheel, which is based onthe information on the state of movement or the steering angle of thevehicle. As shown in FIG. 5 the input 222 of the locator 220 is coupledwith the output 212 of the detector 210. The locator 220 may correspondto the above described locator 120.

In line with the above description, the detector 210 may comprise atleast one of a sensor, an inertial sensor, a micro-mechanical sensor, anacceleration sensor, or a gyroscope for sensing the state of movement ofthe vehicle. In other embodiments the detector 210 may comprise at leastone of an angular sensor, a traverse arm position sensor, a magneticsensor, or an optical sensor, wherein each are configured to sense thesteering angle of the vehicle. The locator 220 may further comprise anadditional input 226, which is indicated in FIG. 5 by the dotted line,for a signal comprising information on a rotational frequency of thewheel. In embodiments at least one of a sensor, an acceleration sensor,an energy harvester, a shock sensor, or a tire pressure monitoringsystem sensor may be coupled to the locator 220, to provide a signalcomprising information on a rotational frequency of the wheel.

In line with what was described above, the locator 220 may also compriseone or more inputs 226 for signals comprising information on a pluralityof rotational frequencies for each of a plurality of wheels. The locator220 may be operable to determine a plurality of locations for theplurality of wheels on the vehicle, based on the information on theplurality of rotational frequencies and on the information of the stateof movement or information on the steering angle. The locator 220 may beoperable to assign predefined positions on the vehicle to each of theplurality of wheels based on the information on the plurality ofrotational frequencies and expected rotational frequencies, wherein theexpected rotational frequencies are based on the information of thestate of movement or the steering angle.

In further embodiments the wheel locator 200 may be operable to verifythe signal comprising information on the rotational frequency of thewheel and the movement or steering signal comprising the information onthe state of movement or the steering angle of the vehicle, before usingthese signals as information to determine the position of the wheel. Thewheel localizer 200 may, for example, be operable to verify that thesignal comprising the information on the rotational frequency of thewheel and the movement or steering signal comprising the information onthe state of movement or steering angle of the vehicle fulfill apredefined relation for a predefined time interval.

FIG. 6 illustrates an embodiment of a wheel localization device 300. Thewheel localization device comprises an input 310 for receiving a signalcomprising information on a state of movement or a steering angle of avehicle. The device 300 further comprises an input 312 for receivingsignals comprising information indicating rotational frequencies of eachof a plurality of wheels of the vehicle, and an input 314 for receivingsignals comprising information indicating a tire parameter for each ofthe plurality of wheels. In the embodiment in FIG. 6 separate inputs310, 312 and 314 are shown. In other embodiments a single input 310 maybe used for all signals instead. The device further comprises a unit 320to assign to each of the plurality of wheels one location of a set ofpredefined locations based on the information on the state of movementor steering angle and the information on the rotational frequencies.

Embodiments further provide a method. FIG. 7 shows a flow chart of anembodiment of a method for locating a position of a wheel on a vehicle.The method comprises obtaining 410 information related to a state ofmovement or related to a steering angle of the vehicle and determining412 the position of the wheel based on the information related to thestate of movement or the steering angle of the vehicle.

FIG. 8 shows a flow chart of an embodiment of a method for determininginformation related to one or more expected rotational frequencies ofone or more wheels of a vehicle. The method comprises determining 610path lengths of the one or more wheels of the vehicle based oninformation related to a path of the vehicle and determining 620 theinformation related to the one or more expected rotational frequenciesof the one or more wheels of the vehicle based on the path lengths ofthe one or more wheels.

Embodiments may further provide a computer program having a program codefor performing one of the above methods, when the computer program isexecuted on a computer or processor. A person of skill in the art wouldreadily recognize that steps of various above-described methods may beperformed by programmed computers. Herein, some embodiments are alsointended to cover program storage devices, e.g., digital data storagemedia, which are machine or computer readable and encodemachine-executable or computer-executable programs of instructions,wherein the instructions perform some or all of the steps of theabove-described methods. The program storage devices may be, e.g.,digital memories, magnetic storage media such as magnetic disks andmagnetic tapes, hard drives, or optically readable digital data storagemedia. The embodiments are also intended to cover computers programmedto perform said steps of the above-described methods or (field)programmable logic arrays ((F)PLAs) or (field) programmable gate arrays((F)PGAs), programmed to perform the steps of the above-describedmethods.

The description and drawings merely illustrate the principles of thedisclosure. It will thus be appreciated that those skilled in the artwill be able to devise various arrangements that, although notexplicitly described or shown herein, embody the principles of thedisclosure and are included within its spirit and scope. Furthermore,all examples recited herein are principally intended expressly to beonly for pedagogical purposes to aid the reader in understanding theprinciples of the disclosure and the concepts contributed by theinventor(s) to furthering the art, and are to be construed as beingwithout limitation to such specifically recited examples and conditions.Moreover, all statements herein reciting principles, aspects, andembodiments of the disclosure, as well as specific examples thereof, areintended to encompass equivalents thereof.

Functional blocks denoted as “means for . . . ” (performing a certainfunction) shall be understood as functional blocks comprising circuitrythat is adapted for performing or to perform a certain function,respectively. Hence, a “means for s.th.” may as well be understood as a“means being adapted or suited for s.th.”. A means being adapted forperforming a certain function does, hence, not imply that such meansnecessarily is performing said function (at a given time instant).

The functions of the various elements shown in the Figures, includingany functional blocks labeled as “means”, may be provided through theuse of dedicated hardware, such as “a processor”, “a determiner”, etc.as well as hardware capable of executing software in association withappropriate software. When provided by a processor, the functions may beprovided by a single dedicated processor, by a single shared processor,or by a plurality of individual processors, some of which may be shared.Moreover, explicit use of the term “processor” or “controller” shouldnot be construed to refer exclusively to hardware capable of executingsoftware, and may implicitly include, without limitation, digital signalprocessor (DSP) hardware, network processor, application specificintegrated circuit (ASIC), field programmable gate array (FPGA), readonly memory (ROM) for storing software, random access memory (RAM), andnon-volatile storage. Other hardware, conventional and/or custom, mayalso be included. Similarly, any switches shown in the Figures areconceptual only. Their function may be carried out through the operationof program logic, through dedicated logic, through the interaction ofprogram control and dedicated logic, or even manually, the particulartechnique being selectable by the implementer as more specificallyunderstood from the context.

It should be appreciated by those skilled in the art that any blockdiagrams herein represent conceptual views of illustrative circuitryembodying the principles of the disclosure. Similarly, it will beappreciated that any flow charts, flow diagrams, state transitiondiagrams, pseudo code, and the like represent various processes whichmay be substantially represented in computer readable medium and soexecuted by a computer or processor, whether or not such computer orprocessor is explicitly shown.

Furthermore, the following claims are hereby incorporated into theDetailed Description, where each claim may stand on its own as aseparate embodiment. While each claim may stand on its own as a separateembodiment, it is to be noted that—although a dependent claim may referin the claims to a specific combination with one or more otherclaims—other embodiments may also include a combination of the dependentclaim with the subject matter of each other dependent claim. Suchcombinations are proposed herein unless it is stated that a specificcombination is not intended. Furthermore, it is intended to include alsofeatures of a claim to any other independent claim even if this claim isnot directly made dependent to the independent claim.

It is further to be noted that methods disclosed in the specification orin the claims may be implemented by a device having means for performingeach of the respective steps of these methods.

Further, it is to be understood that the disclosure of multiple steps orfunctions disclosed in the specification or claims may not be construedas to be within the specific order. Therefore, the disclosure ofmultiple steps or functions will not limit these to a particular orderunless such steps or functions are not interchangeable for technicalreasons.

Furthermore, in some embodiments a single step may include or may bebroken into multiple substeps. Such substeps may be included and part ofthe disclosure of this single step unless explicitly excluded.

What is claimed is:
 1. A system for locating a position of a wheel on avehicle, comprising: a detector configured to obtain information relatedto a state of movement of the vehicle; and a locator configured todetermine the position of the wheel based on the information related tothe state of movement of the vehicle.
 2. The system of claim 1, whereinthe information related to the state of movement comprises informationon a rotation of the vehicle.
 3. The system of claim 1, wherein thedetector comprises at least one of an inertial sensor, amicro-mechanical sensor, an acceleration sensor, or a gyroscope, whereineach are configured to generate a signal based on which the state ofmovement is detectable.
 4. The system of claim 1, wherein the locator isoperable to further use information on a rotational frequency of thewheel to determine the position of the wheel based on the informationrelated to the state of movement of the vehicle.
 5. The system of claim4, wherein the locator is operable to use information on rotationalfrequencies for each of a plurality of wheels on the vehicle anddetermine a position for each of the plurality of wheels on the vehiclebased on the information on the plurality of rotational frequencies andthe information related to the state of movement of the vehicle.
 6. Thesystem of claim 5, wherein the locator is operable to assign predefinedpositions on the vehicle to each of the plurality of wheels based on theinformation on the plurality of rotational frequencies and expectedrotational frequencies, wherein the expected rotational frequencies arebased on the information related to the state of movement.
 7. The systemof claim 4, further comprising an acceleration sensor, an energyharvester, or a tire pressure monitoring system sensor configured toobtain the information on the rotational frequency of the wheel.
 8. Thesystem of claim 4, wherein the system is operable to verify a signalindicating the rotational frequency of the wheel and a signal indicatingthe state of movement of the vehicle before using the signals asinformation to determine the position of the wheel.
 9. The systemaccording to claim 8, wherein the system is operable to verify that therotational frequency of the wheel and a rotational rate of the vehicle,which is based on the state of movement of the vehicle, fulfill apredefined relation for a predefined time interval.
 10. The system ofclaim 4, wherein the locator is operable to determine the position ofthe wheel when changes of the state of movement of the vehicle are belowa predefined threshold for a predefined time interval.
 11. The system ofclaim 4, wherein the locator is operable to determine a correctedrotational frequency of the wheel based on information on a tirepressure of a tire of the wheel and based on the rotational frequency ofthe wheel, and wherein the locator is operable to determine the positionof the wheel based on the corrected rotational frequency.
 12. A wheellocalizer for locating a position of a wheel on a vehicle, comprising: adetector configured to output a movement signal comprising informationon a state of movement of the vehicle; and a locator configured toreceive the movement signal, and generate a location signal comprisinginformation on the position of the wheel based on the information on thestate of movement of the vehicle.
 13. The wheel localizer of claim 12,wherein the detector comprises at least one of a sensor, an inertialsensor, a micro-mechanical sensor, an acceleration sensor, or agyroscope, wherein each are configured to sense the state of movement ofthe vehicle.
 14. The wheel localizer of claim 12, wherein the locatorfurther comprises an input configured to receive a signal comprisinginformation on a rotational frequency of the wheel.
 15. The wheellocalizer of claim 14, wherein at least one of a sensor, an accelerationsensor, an energy harvester, or a tire pressure monitoring system sensoris coupled to the locator.
 16. The wheel localizer of claim 14, furtherconfigured verify a signal comprising information on the rotationalfrequency of the wheel and the movement signal comprising theinformation on the state of movement of the vehicle, before using thesesignals as information to determine the position of the wheel.
 17. Thewheel localizer of claim 16, further configured to verify that thesignal comprising the information on the rotational frequency of thewheel and the movement signal comprising the information on the state ofmovement of the vehicle fulfill a predefined relation for a predefinedtime interval.
 18. The wheel localizer of claim 12, wherein the locatorcomprises one or more inputs configured to receive signals comprisinginformation on a plurality of rotational frequencies for each of aplurality of wheels, and wherein the locator is configured to determinea plurality of locations for the plurality of wheels on the vehicle,based on the information on the plurality of rotational frequencies andon the information of the state of movement.
 19. The wheel localizer ofclaim 18, wherein the locator is configured to assign predefinedpositions on the vehicle to each of the plurality of wheels based on theinformation on the plurality of rotational frequencies and expectedrotational frequencies, wherein the expected rotational frequencies arebased on the information of the state of movement.
 20. The wheellocalizer of claim 12, wherein the locator further comprises an inputconfigured to receive a signal comprising information on a tire pressureof a tire of the wheel, and wherein the locator is operable to determinea corrected rotational frequency of the wheel based on the informationon the tire pressure of the tire of the wheel, and wherein the locatoris operable to output the information on the location of the wheel basedon the corrected rotational frequency.
 21. A wheel localization device,comprising: an input configured to receive a signal comprisinginformation on a state of movement of a vehicle, signals comprisinginformation indicating rotational frequencies of each of a plurality ofwheels of the vehicle, and signals comprising information indicating atire parameter for each of the plurality of wheels; and a unitconfigured to assign to each of the plurality of wheels one location ofa set of predefined locations based on the information on the state ofmovement and the information on the rotational frequencies.
 22. A methodfor locating a position of a wheel on a vehicle, comprising: obtaininginformation related to a state of movement of the vehicle; anddetermining the position of the wheel based on the information relatedto the state of movement of the vehicle.
 23. The method of claim 22further comprising using information on a rotational frequency of thewheel for the determining of the position of the wheel based on theinformation related to the state of movement.
 24. The method of claim23, wherein the using comprises using information on rotationalfrequencies of a plurality of wheels on the vehicle, and wherein thedetermining comprises determining positions for each of the plurality ofwheels on the vehicle based on the information on the plurality ofrotational frequencies and the information related to the state ofmovement.
 25. The method of claim 24, wherein the determining comprisesassigning predefined positions on the vehicle to each of the pluralityof wheels based on the information on the plurality of rotationalfrequencies and expected rotational frequencies, wherein the expectedrotational frequencies are based on the information related to the stateof movement.
 26. The method of claim 23, further comprising verifying asignal indicating the rotational frequency of the wheel and a signalindicating the state of movement of the vehicle, before using thesignals as information to determine the position of the wheel.
 27. Themethod of claim 26, wherein the verifying comprises verifying that therotational frequency of the wheel and a rotational rate of the vehicle,which is based on the state of movement of the vehicle, fulfill apredefined relation for a predefined time interval.
 28. The method ofclaim 23, further comprising correcting the rotational frequency of thewheel based on information on a tire pressure of a tire of the wheel todetermine a corrected rotational frequency, and wherein the determiningof the position of the wheel is based on a corrected rotationalfrequency.
 29. A computer program having a program code on anon-transitory media for performing, when the computer program isexecuted on a computer or on a processor, a method for locating aposition of a wheel on a vehicle, comprising: obtaining informationrelated to a state of movement of the vehicle; and determining theposition of the wheel based on the information related to the state ofmovement of the vehicle.